I am in the process of setting up beer smith on my mac for my system and am running into some problems and was wondering if any of you could answer my questions.

1. I have to set my mash tun coefficient to around .79 to get the correct temperature drop(20 deg) of my infusion water before I add my grain. My mash tun is a 15.5 gal keg wrapped in insulation. Is this correct or am i using this wrong?

2. The est O.G. i was getting from Qbrew versus Beersmith with the same efficiency and grain extractions is a lot higher in Qbrew. Beersmith is actually closer to the real O.G.'s I have been getting lately(may not have been my thermometer after all) What is the best efficiency setting for a single infusion cooler(basically what I have) and fly sparing?

1) I use beersmith to calculate my mash infusion temperature. I just use the equipment default settings for the "Stainless Kegs (10Gal) - All Grain" and Water/Grain Ratio of 1.25 qt/lb. The temperatures work out pretty good. Are you really losing 20F when mashing in? I do not see a parameter called mash tun coefficient. However, there is the mash tun specific heat.

2) I have only used 75% efficiency but always get slightly higher. I don't mind the slightly higher alcohol. It all depends on your process (e.g. how slow you sparge, false bottum, sparge temp, etc.).

You are right it's mash tun specific heat, my bad. I was going to leave it @ 75% since that seems to be what I have hit the last few times and Im with you a little more alchol is a good thing IMHO. I just don't like coming out low. Well I got a new thermometer, hydrometer(broke mine), and tweaked my recipe with beer smith so we will see how things go Thurs. We been so busy @ work I had to take the day off just so I could brew. Making a scottish ale.